This invention relates to transmissions, and more particularly to an improved automotive transmission of the type which combines the features of a positive gear drive, and a transmission which can be shifted automatically in response to variations in the speed of a vehicle's drive shaft. Even more particularly this invention relates to an improved two-way roller clutch mechanism for use in transmissions of the type described.
Most automotive transmissions normally comprise either the stick shift or manually operated variety, which relies on the manual shifting gears for transmitting drive from the vehicle drive shaft to the wheels of the vehicle, or the so-called automatic transmission, which frequently employs hydraulically or centrifugally actuated clutch mechanisms which respond to variations in the speed of the drive shaft.
The present invention combines features of both of the above-noted drive systems. For example, the transmission disclosed herein utilizes two series of intermeshed gears for transmitting drive to a driven shaft, but the two series always remain engaged or intermeshed with each other, rather than being shifted into and out of engagement with each other as in the case of conventional stick shifts. Furthermore the gears on the driven shaft are selectively coupled thereto by novel two-way roller clutch mechanisms, which can be selectively and hydraulically operated by, for example, a micro-computer, or the like. The computer can be made selectively and successively to actuate or deactuate the clutch mechanism in response to changes in the speed of the drive shaft, thereby to make the most efficient use of the fossil fuel that is used to operate the associated power supply - e.g. an IC engine.
As disclosed in U.S. Pat. Nos. 3,820,406 and 3,294,208, so-called one-way roller clutches, which function to lock or prevent rotation in one direction, and to allow friction-free or free wheeling rotation in the opposite direction, have been employed heretofore in connection with drives for starters for IC engines, and for grinding wheels. Various uses for two-way roller clutches are taught by U.S. Pat. Nos. 3,750,782; 2,028,876; 3,907,083; and 4,076,108. Although the last of these patents suggests the use of a two-way roller clutch in an automotive transmission, the drive illustrated in the patent has nothing to do with a transmission of the type in which two sets of gears are constantly intermeshed.
It is an object of this invention, therefore, to provide an improved positive drive transmission which can be controlled automatically to shift from one gear sequence to another in response to changes in engine speeds.
Still another object of this invention is to provide, for a transmission of the type described, an improved two-way roller clutch mechanism for selectively coupling a plurality of different gears one by one to an associated driven shaft.
Other objects of the invention will be apparent hereinafter from the specification and from the recital of the appended claims, particularly when read in conjunction with the accompanying drawings.